This is the C8 mid-engine Chevy Corvette - Page 18 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Dadhawk · 12-07-2018, 03:22 PM

Video of the mid-engine running at Sebring at night. Good recording of the engine sound..

[ame]https://www.youtube.com/watch?v=kfg71KgtxO4[/ame]

humfrz · 12-07-2018, 03:44 PM

Quote:

Originally Posted by Dadhawk

Video of the mid-engine running at Sebring at night. Good recording of the engine sound..

Sounds like a real close ratio transmission.

humfrz

Horrid_Funk · 12-07-2018, 06:32 PM

Quote:

Originally Posted by humfrz

Sounds like a real close ratio transmission.

humfrz

Yeah those 5 downshift corners have it sounding like a proper race car. It absolutely wails like a flat plane, too.

Dadhawk · 12-07-2018, 09:36 PM

I'm liking the profile better than I thought I would as well

chipmunk · 12-15-2018, 04:26 PM

The first variant will be the LT2 (similar to LT1). I'm not sure what the delay is on the vehicle side, but powertrain side is all go!

Next, the flat-plane V8 with 5.5L naturally aspirated. Red line is 8600 rpm. I don't quite remember the power figures. Due to the flat plane, there are very very high vibrations horizontally. Drivers were complaining about fingers going numb after driving! I know Ford managed a flat-plane too, but their crank shaft is a lot heavier with the balancing counterweights. So they basically "cheated". But the LT6 has a much lighter crank.

Later on, the LT6 will be given twin-turbos, and renamed the LT7. This is a beast, with about 850 hp. I am not directly involved with the LT7, so I can't give any more info than that.

The LT6 has a lot of vibrations and exhaust overheating issues. It is benchmarked against the Ferrari 488. But no one has ever done a flat-plane engine with such high displacement (5.5L).

Ultramaroon · 12-15-2018, 04:39 PM

Quote:

Originally Posted by chipmunk

I know Ford managed a flat-plane too, but their crank shaft is a lot heavier with the balancing counterweights. So they basically "cheated". But the LT6 has a much lighter crank.

Why is that cheating?

chipmunk · 12-15-2018, 05:09 PM

Quote:

Originally Posted by Ultramaroon

Why is that cheating?

"Cheating" in the sense that, the benefits of using a flat-plane are negated by using a heavy crank, so there really isn't a point except to brag about it!

chipmunk · 12-15-2018, 05:13 PM

And because of the high red line, there is a lot of oil starvation at the journals. As of May 2018, there was no solution to it. No clue what all they did since then to mitigate

Ultramaroon · 12-15-2018, 05:41 PM

Quote:

Originally Posted by chipmunk

"Cheating" in the sense that, the benefits of using a flat-plane are negated by using a heavy crank, so there really isn't a point except to brag about it!

Take some out of the flywheel and call it good. First manage flutter. Then get what you can from it.

chipmunk · 12-15-2018, 06:43 PM

Quote:

Originally Posted by Ultramaroon

Take some out of the flywheel and call it good. First manage flutter. Then get what you can from it.

It's a Tremec dual clutch. Not sure how much difference that would make.
With such high piston speeds and rotating/reciprocating con rods, pins, journals, etc., you benefit more from having a lighter crank than a lighter flywheel.

8600rpm from a 5.5L.... I should tip my hat to my ex-colleagues at GM!

chipmunk · 12-15-2018, 06:48 PM

By the way, the flywheel mass actually helps dampen out the crank torsional vibrations. It helps a lot with the durability of the accessory drive system. In turn, a smooth accessory drive makes life a lot easier for the block, front cover & head, wherever they are bolted.
Lighter flywheels for road applications is just a fad.

gymratter · 12-15-2018, 06:59 PM

Quote:

The mid engine Corvette will not debut next month at the 2019 North American International Auto Show in Detroit. That much you probably already know. But what you probably don’t know is why.

According to sources familiar with the matter speaking to GM Authority on the basis of anonymity, engineers have uncovered a major electrical issue with the future Corvette during the development process. From what we gather, the vehicle’s electrical system can’t carry the load necessary to support the necessary components.

To address the issue, engineers will need to re-engineer the vehicle’s electrical system. Naturally, changes made to the sports car will also need to be coordinated with suppliers involved in providing GM with the electrical components, as well as any associated equipment. The undertaking will delay the mid-engine Corvette project by six months.

Despite this, GM/Chevrolet should still be able to launch the mid engine Corvette for the 2020 model year, though a 2021 model year launch is not entirely off the table.

Stay tuned to GM Authority for more Corvette news and mid engine Corvette news.

http://gmauthority.com/blog/2018/12/...ssue-breaking/

Ultramaroon · 12-15-2018, 07:17 PM

Quote:

Originally Posted by chipmunk

It's a Tremec dual clutch. Not sure how much difference that would make.
With such high piston speeds and rotating/reciprocating con rods, pins, journals, etc., you benefit more from having a lighter crank than a lighter flywheel.

Then leave it there. I'm saying that based on your description of the differences between the two powerplants, I agree with Ford's choice of adding more mass to minimize the shaking forces. It's better for the longevity of the whole vehicle.

Quote:

Originally Posted by chipmunk

Lighter flywheels for road applications is just a fad.

chipmunk · 12-15-2018, 07:30 PM

Not quite sure what the delay with the LT2 is.
When I worked there, I worked almost solely on the LT6. By then, the development of the LT2 was already over and the Corvette mules were running around. So I'm not an expert with the LT2.
There is just way too much heat under the trunk for the MR layout, that much I know.

12-07-2018, 03:22 PM	#239
Dadhawk Senior Member Join Date: Feb 2012 Drives: '13 FR-S (#3 of 1st 86) Location: Powder Springs, GA Posts: 20,104 Thanks: 39,658 Thanked 25,434 Times in 11,599 Posts Mentioned: 187 Post(s) Tagged: 4 Thread(s)	Video of the mid-engine running at Sebring at night. Good recording of the engine sound.. [ame]https://www.youtube.com/watch?v=kfg71KgtxO4[/ame] __________________ Olivia 05/03/2012 - 01/06/2024. 231,146 glorious miles. Visit my Owner's Journal where I wax philosophic on all things FR-S Post your 86 or see others in front of a(n) (in)famous landmark. What fits in your 86? Show us the "Junk In Your Trunk".

12-07-2018, 09:36 PM	#242
Dadhawk Senior Member Join Date: Feb 2012 Drives: '13 FR-S (#3 of 1st 86) Location: Powder Springs, GA Posts: 20,104 Thanks: 39,658 Thanked 25,434 Times in 11,599 Posts Mentioned: 187 Post(s) Tagged: 4 Thread(s)	I'm liking the profile better than I thought I would as well Attached Images __________________ Olivia 05/03/2012 - 01/06/2024. 231,146 glorious miles. Visit my Owner's Journal where I wax philosophic on all things FR-S Post your 86 or see others in front of a(n) (in)famous landmark. What fits in your 86? Show us the "Junk In Your Trunk".

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12-15-2018, 04:26 PM	#243
chipmunk Senior Member Join Date: Mar 2017 Drives: _ Location: _ Posts: 440 Thanks: 50 Thanked 178 Times in 104 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	The first variant will be the LT2 (similar to LT1). I'm not sure what the delay is on the vehicle side, but powertrain side is all go! Next, the flat-plane V8 with 5.5L naturally aspirated. Red line is 8600 rpm. I don't quite remember the power figures. Due to the flat plane, there are very very high vibrations horizontally. Drivers were complaining about fingers going numb after driving! I know Ford managed a flat-plane too, but their crank shaft is a lot heavier with the balancing counterweights. So they basically "cheated". But the LT6 has a much lighter crank. Later on, the LT6 will be given twin-turbos, and renamed the LT7. This is a beast, with about 850 hp. I am not directly involved with the LT7, so I can't give any more info than that. The LT6 has a lot of vibrations and exhaust overheating issues. It is benchmarked against the Ferrari 488. But no one has ever done a flat-plane engine with such high displacement (5.5L).

12-15-2018, 05:13 PM	#246
chipmunk Senior Member Join Date: Mar 2017 Drives: _ Location: _ Posts: 440 Thanks: 50 Thanked 178 Times in 104 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	And because of the high red line, there is a lot of oil starvation at the journals. As of May 2018, there was no solution to it. No clue what all they did since then to mitigate

12-15-2018, 06:48 PM	#249
chipmunk Senior Member Join Date: Mar 2017 Drives: _ Location: _ Posts: 440 Thanks: 50 Thanked 178 Times in 104 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	By the way, the flywheel mass actually helps dampen out the crank torsional vibrations. It helps a lot with the durability of the accessory drive system. In turn, a smooth accessory drive makes life a lot easier for the block, front cover & head, wherever they are bolted. Lighter flywheels for road applications is just a fad.

12-15-2018, 07:30 PM	#252
chipmunk Senior Member Join Date: Mar 2017 Drives: _ Location: _ Posts: 440 Thanks: 50 Thanked 178 Times in 104 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	Not quite sure what the delay with the LT2 is. When I worked there, I worked almost solely on the LT6. By then, the development of the LT2 was already over and the Corvette mules were running around. So I'm not an expert with the LT2. There is just way too much heat under the trunk for the MR layout, that much I know.

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